Bo Hansen DI layout

[Rellister]

Hi Bo & Everybody,
Finished 2xDIs with Lundahls today, they work and sound excellent.
Tested with my old Precision, sounds very good.
Clean with lots of low end. Again, thanks for a cool project!

Rune

 

[zebra50]

I thought I'd share these pics. Some friends of mine have a lot of acoustic instruments, and they wanted some DI boxes with a mute switch built in, so they could switch instruments or tune up on stage.

I built a pair of these little stomp-DI's for them, based on Bo's design. The DI and amp outs are muted by the footswitch, and there is an additional 'through' output for the tuner that is always on.

To minimise switch popping at the output, I needed to add a 1 meg pull down resistor at the switch. Also, if you use the LED on the board as the indicator lamp and switch it, then that will cause popping too, so you have to watch that! 

Anyway, they sound good, are very useful. I like them so much that I'm going to make a couple for myself. Thanks again to everyone who contributed to this.

Stewart

 

[flaheu]

Zebra,

I'm interested in your version, where did you put the "tuner out", have you "doubled" the amp out and put the mute after the other one to stop feeding the eventual amp ?

Thanks

 

[zebra50]

Hi!

For the tuner output I just paralleled the input - very simple.

Stewart

 

[chrispbass]

Nice work Stewart. Are those cases readily available, can't say I've seen any like that for sale anywhere?
Chris

 

[zebra50]

Hi Chris,

The cases are really cool and are reasonably priced, even with postage from the US. They are nice quality cast aluminium and were really easy to machine, even on my feeble drill press!
I found them on Ebay - I searched for stompbox enclosure or something similar. Here you go...

http://shop.ebay.co.uk/pedalenclosures/m.html?_trksid=p4340.l2562

They had unfinished ones when I looked for a couple of bucks less, but those painted ones look really nice too.

 

[chrispbass]

Hi Chris,

The cases are really cool and are reasonably priced, even with postage from the US. They are nice quality cast aluminium and were really easy to machine, even on my feeble drill press!
I found them on Ebay - I searched for stompbox enclosure or something similar. Here you go...

http://shop.ebay.co.uk/pedalenclosures/m.html?_trksid=p4340.l2562

They had unfinished ones when I looked for a couple of bucks less, but those painted ones look really nice too.

Cheers Stewart, just the job with a nice retro vibe about them. May have to invest
C

 

[flaheu]

Thanks Zebra50,

It's obvious whan you look at the wiring !
I'm getting old, I should wear glasses  :

Thanks

 

[Holger]

Just to share, and already posted in Frank's German forum: I managed somehow to put two channels in the little modushop case.

 

[lorcan]

Hi all,

here is my build with an audiomaintenance 9045 transfo (http://www.audiomaintenance.com/acatalog/CA-18-VTB9045_extended_info.html)

I did my own layout using Eagle cad to fit this in a Hammond 1590B die-cast box, which is often used for guitar FX pedals.
It looks very sturdy, and it's quite a tight fit, but it works and sounds great
Thanks for this great project, Bo  8)

 

[lorcan]

Gutshots ...

 

[lorcan]

And finally the pcb (pdf), layout & components

 

[culteousness1]

Hi all,

just finished my Oxford Edition:

Working from first fire-up and really nice sounding.

Thanks to Bo, Soeren, Luny Tune, Gustav and Frank!

Cheers,
Carsten

 

[kante1603]

O.k, here are mine (the upper ones are duals-holger "triggered" me doing that ;D)
Cases are modushop from italy,panels from NRG (thx Frank!),all with Haufe transformers.

They have nice black screws on the front in the final version.

Best,

Udo.

 

[Edward]

Hi!


I just ordered my first Carnhill transformers, modell VTB9045, and im going to try and build a Bo Hansen Di box using these. I have recently finished a 2ch version with Lundahl LL1538XL transformers and that turned out great! Im really happy with the result. Thank you Bo, and Gustav for the PCB. Thanks also to all who posted here for great tips and tricks and inspiration.

My question is how to connect the pins on the Carnhill VTB9045 transformer to the tranformer "holes" on the PCB? Im a little unsure and a little too incompetent myself to make up my mind.

I have read that others have succseeded with the same project and if anyone would like to share their experience i would be very thankfull.


Kind regards,


Edward.

 

[Bo Hansen]

Edward,

To match my DI-box you shall do this pin configuration on the Carnhhill VTB-9045

link pin 8+9 (not connected to pc-card)
pin 7 connect to pc-card point 6
link pin 6+10 and connect to pc-card point 8

link pin 2+3 and connect to pc-card point 1
link pin 4+5 and connect to pc-card point 2

NOTE about transformer case grounding
Use a solder-lug with a screw to one of the transformer fixing holes, and link also this to pin 6+10
Do not screw the transformer case direct to the DI-box metal box/case, it must be isoleted from the metal box.

--Bo

 

[blue_lu]

finally finished my di box. will put it through its paces soon with rhodes and synths...
build is not very clean, but I am beginner with almost no tools - so I had to drill the box by hand and so on. came out alright I think!

twp channels

close up

working!

 

[Bo Hansen]

Matt,

The transformer you use have a bit more loss compare with Lundahl LL1538, so it is ok that you must use a bit more gain.

Two 47 ohms resistors connected in series, is near same as a 100 ohm resistor, so this is also ok.

--Bo

 

[funkymonksf]

If possible could someone guide me in how I could add a volume control and a simple tone control to this circuit. I need to be able to adjust these factors on stage. It's for an acoustic guitar that has no on-board controls. Any advice or ideas are much appreciated.

-Brice

 

[Bo Hansen]

Brice,

It is difficult to direct implant your wishes with volume and tone control on this circuit since it only consists of a two stage emitter folower with no gain.

Your wishes need a completely different circuit design to work well.

If you want to use a balanced phantom powered microphone input as receiver for your intended acoustic guitar pre amp, you can use the original DI-box design as a output amp, and then add a front end amplifier with gain control, bass and treble control .

This add-on amplifier may consist of two transistors which is also fed by the phantom power systems that are already on the original DI-box PC-Card.

Tell me a little bit more what kind of guitar pickups you intend to use, and what kind of an equalizer you want, and what you plan to connect the pre amp to.

Maybe if I get time, I can design something simple and clever to you and others who may be interested in something similar.

--Bo